Error: Call to a member function payWith()

hola, podrias ayudarme con este error, luego de hacer la instalacion en laravel 7, al ejecutar una consulta de prueba en postman me genera este error: Error: Call to a member function payWith() on int in file /var/www/ok/app/Http/Controllers/Payupay.php on line 63 este my controller Payupay.php

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use Auth;
use Validator;
use Alexo\LaravelPayU\Payable;
use App\Order;

class Payupay extends Controller
{
   public function index(Request $request) {

      $validator = Validator::make($request->all(), [ 
                'card_number' => 'required', 
                'card_expiration' => 'required', 
                'card_security_code' => 'required', 
                'payment_method'=> 'required', 
                'value'=> 'required', 
                'cardName'=> 'required', 
                'dni'=> 'required', 
            ]);
    if ($validator->fails()) { 
                return response()->json(['error'=>$validator->errors()], 401);            
            }

          $input = $request->all(); 

         $card_number = $input['card_number'] ;
         $card_expiration = $input['card_expiration'];
         $card_security_code = $input['card_security_code'];
         $payment_method = $input['payment_method'];
         $value = $input['value'];
         $cardname = $input['cardName'];
         $dni = $input['dni']; 

         $payment_method  = strtoupper($payment_method );
         //$payment_method='MASTERCARD';
         $reference = time();

$data = [   
            \PayUParameters::REFERENCE_CODE => $reference,
            \PayUParameters::DESCRIPTION => "Pago suscripcion  Apps",
            \PayUParameters::VALUE => $value,
            \PayUParameters::CURRENCY => "COP",
            \PayUParameters::PAYER_NAME => $cardname,
            \PayUParameters::PAYER_EMAIL =>"mail@yahoo.com",
            \PayUParameters::PAYER_CONTACT_PHONE => "0123456789",
            \PayUParameters::CREDIT_CARD_NUMBER => $card_number,
            \PayUParameters::CREDIT_CARD_EXPIRATION_DATE => $card_expiration,
            \PayUParameters::CREDIT_CARD_SECURITY_CODE=> $card_security_code,
            \PayUParameters::PAYMENT_METHOD => $payment_method ,
            \PayUParameters::INSTALLMENTS_NUMBER => "1",                    
        ];

$order = $reference ;

    $order->payWith($data, function($response, $order) {
    if ($response->code == 'SUCCESS') {
            $response['error'] = false;
           return response([
           'Result' => "Success",
            'data' => $response
             ]);

    } else {
        $response['error'] = true;
        return response([
           'Result' => "Success",
            'data' => $response
             ]);
    }
      }, function($error) {
           // ... Manejo de errores PayUException, InvalidArgument
     }); 
}
}

` No se si el order escribe algun conteido en mysql o como podria retirar el $order, ya que no voy a llevar ningun registro aparte de las transacciones, solo reigstrar la operacion y devoler un response, seria algo como:

payWith($data,$response) {
    if ($response->code == 'SUCCESS') {
            $response['error'] = false;
           return response([
           'Result' => "Success",
            'data' => $response
             ]);
    } else {
        $response['error'] = true;
        return response([
           'Result' => "Success",
            'data' => $response
             ]);
    }
      }

de antemano gracias por su ayuda

alejogutierrez / laravel-payu

Error: Call to a member function payWith() #6